The only thing I've found wrong with TTI headers other than cost is replacing the starter, What a pain!!! Of course it may be easier if the Demon had a small block.
on the smallblock tti headers it took some thinking, if i remember it right i had to put the starter in behind the headerstubes "uppside down and backwards" then twist it around behind the headertubes, and that was with a ministarter but i got it in there without no dissasembly ;)